Testing older floppy drives on newer machines

[Unknown_K]

Has anybody ever tried to test older 5.25" FH 180K drives on newer hardware? I have a box of disk drives I want to test and one is a 180K IBM (I asume it is single sided).

Also has anyone ever ran into a 5.25" that formats 720K disks? I have a Teac 55FV-35-u and read somewhere it does 720K. I know there were BIOS overlays for 1.2MB drives to format 360K as 720/800K. I wonder if that drive is just a tricked out 1.2MB drive.

 

[Chuck(G)]

Has anybody ever tried to test older 5.25" FH 180K drives on newer hardware? I have a box of disk drives I want to test and one is a 180K IBM (I asume it is single sided).

Depends on the vintage. Some of the older 180/160K SS drives had slow seek times. While some packages (modesty forbids) allow you to specify the seek time, the default in newer machines is generally too fast. But once you're on a track, it should work. There's no real difference between single- and double-sided drives, except that the head select goes nowhere.

Also has anyone ever ran into a 5.25" that formats 720K disks? I have a Teac 55FV-35-u and read somewhere it does 720K. I know there were BIOS overlays for 1.2MB drives to format 360K as 720/800K. I wonder if that drive is just a tricked out 1.2MB drive.

There were plenty of those--just look at some of the older CP/M boxes for examples. Teac FD55F drives are 96 tpi, so they do 720K naturally. Just declare them as 3.5" 720K drives in your BIOS setup.

One can even jumper many 1.2MB drives to do 720K. Just set the jumpers for 300 RPM operation. Piece of cake.

Just be sure to use 2D (360K) media.

 

[billdeg]

about testing on a newer box...No, I have a test system set up for testing drives. Wouldn't that be easier? Any old clone will do.
bd

 

[Chuck(G)]

about testing on a newer box...No, I have a test system set up for testing drives. Wouldn't that be easier? Any old clone will do.
bd

The floppy interface, hardware-wise, hasn't changed substantially since the 5170. Still has a uPD765-based controller, uses 8237-type DMA channel 2 and IRQ6.

The only modern modifications are usually the lack of wiring for a second floppy drive (i.e. motherboards are configured for only one legacy drive). (There's usually a 1Mbps support for 2.88MB drives as well, but that's just an addition).

But under it all, it's the same old nag. Only the software has changed.

PC design engineers hate the floppy controller, as it necessitates a simulation of the ISA bus in the Southbridge chip. That's probably why many newer machines don't have legacy floppy support.

 

[wolfie]

i usually use a pentium 2 as a bench system for testing hardware and it works fairly efficiently. it is alot faster and i find it more reliable than most of my 486 and p1 systems. i use multiple hard drive for different operating systems.

 

[Unknown_K]

A few of the drives don't have the normal molex connection for power.

A couple 5.25" drives ripped out of a Sanyo DOS compatible didn't work on the 360k setting, I guess I will have to look up the specs and see if something needed jumpered.

 

[billdeg]

One underlying point here is that it's not necessary to have vintage everything when testing, you need to remove as many "not sure if that works" variables so that you can focus on the one thing that you're really sure is unknown.

I am going to be hosting a workshop at the end of January, and I think we're going to focus primarily on disk drive repair, bootstrapping, etc. Without working drives many computers are just heaters.

 

[Chuckster_in_Jax]

Has anybody ever tried to test older 5.25" FH 180K drives on newer hardware? I have a box of disk drives I want to test and one is a 180K IBM (I asume it is single sided).

Dave Dunfields site www.classiccmp.org has some good information about drive/controller abilities. Read info on his utility "TestFDC" .

http://www.classiccmp.org/dunfield/img/

I have a Compaq 386 box with an Adaptec 1522A controller in it for generating floppies from disk images. According to Dave's list, this controller is one the the most compatible.

Also has anyone ever ran into a 5.25" that formats 720K disks? I have a Teac 55FV-35-u and read somewhere it does 720K.

Your Teac 55FV is a 720K drive.

There are three half-height 5.25" 720K floppy drives on eBay right now. They have already been relisted a couple of times. Surprising since they are fairly rare. The full height units are almost impossible to find.

http://cgi.ebay.com/TEAC-FD-55FR-51...C_Drives_Storage_Internal?hash=item1e5959d241

http://cgi.ebay.com/TEAC-FD-55F-03-...C_Drives_Storage_Internal?hash=item48387a9272

http://cgi.ebay.com/TEAC-FD-55FR-51...C_Drives_Storage_Internal?hash=item1c0e5011a2